2-Propanone, 1,3-dihydroxy-, aldol reaction

It seems unlikely that this reaction could occur in quite the same way as in the laboratory aldol reaction, because the enolate anion of the donor molecule (dihydroxypropanone) is not expected to be formed in significant amount of the pH of living cell. In fact there is strong evidence that the enzyme behaves as amino (ENH2) compound and reacts with carbonyl group of dihydroxy propanone to form an imine. This... 

In the limited sense that this reaction may be viewed as an attack by a nucleophilic species on an aldehyde, it resembles the chemical aldol condensation and the enzymic aldolase condensation. Recent studies of the latter reaction have demonstrated the formation of a l,3-dihydroxy-2-propanone phosphate-aldolase complex, capable of exchanging a carbon-... 

Aldolizations of trioses, with formation of hexoses, have been observed in several investigations. Meyerhof estimated that the triose-hexose equilibrium mixture from the condensation of OL-glycerose with 1,3-dihydroxy-2-propanone (in trisodium phosphate solution) contained 92% of hexose. Berl and Feazel, in their kinetic examination of this aldolization in sodium hydroxide solution, were unable to detect any triose by paper chromatography at the end of the reactions. Pyruvaldehyde formation complicates any glycerose or 1,3-dihydroxy-2-propanone reaction in alkaline medium, and this fact probably accounts for some of the disappearance of triose from these mixtures. Nevertheless, aldolizations of these short-chain sugars are side reactions to be reckoned with, whenever circumstances permit their occurrence. 

---